package club.zhcs.titans.utils.codec;

import java.io.IOException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import org.nutz.log.Log;
import org.nutz.log.Logs;
import org.nutz.repo.Base64;

/**
 * 用于ios的对称加密
 * 
 * @author wkipy
 *
 */
public class DES {

	private final static String DES = "DES";

	public static String DEFAULT_KEY = "abcdefgh";

	private static Log log = Logs.get();

	public static String encrypt(String data) {
		return encrypt(data, DEFAULT_KEY);
	}

	public static String decrypt(String data) {
		return decrypt(data, DEFAULT_KEY);
	}

	/**
	 * Description 根据键值进行加密
	 * 
	 * @param data
	 * @param key
	 *            加密键byte数组
	 * @return
	 * @throws Exception
	 */
	public static String encrypt(String data, String key) {
		byte[] bt = null;
		try {
			bt = encrypt(data.getBytes(), key.getBytes());
		} catch (Exception e) {
			log.error(e);
		}
		return Base64.encodeToString(bt, false);
	}

	/**
	 * Description 根据键值进行解密
	 * 
	 * @param data
	 * @param key
	 *            加密键byte数组
	 * @return
	 * @throws IOException
	 * @throws Exception
	 */
	public static String decrypt(String data, String key) {
		if (data == null)
			return null;

		byte[] buf = Base64.decode(data);
		byte[] bt = null;
		try {
			bt = decrypt(buf, key.getBytes());
		} catch (Exception e) {
			log.error(e);
		}
		return new String(bt);
	}

	/**
	 * Description 根据键值进行加密
	 * 
	 * @param data
	 * @param key
	 *            加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成加密操作
		Cipher cipher = Cipher.getInstance(DES);

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}

	/**
	 * Description 根据键值进行解密
	 * 
	 * @param data
	 * @param key
	 *            加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成解密操作
		Cipher cipher = Cipher.getInstance(DES);

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}
}
